With an interchangeable lens type camera, if information on the full-aperture value and minimum-aperture value of each interchangeable lens can be transmitted to the camera body, it is convenient for the photographer. If this is possible, for instance the full-aperture value and minimum-aperture value of a lens coupled to the camera body can be displayed in the finder. In light metering with a shutter priority type automatic exposure camera, although a lens having a full-aperture value f 4 is coupled to the camera body, sometimes an indication (for instance f 2) brighter than that is made. If a photographing operation is carried out in this state, an exposure error is caused. Therefore, in this case it is necesary to provide a warning means or to transmit the full-aperture value information from the lens to the camera body. The same is true of the minimum-aperture value. However, there is no relationship between the full-aperture value and the minimum-aperture value of a lens and, therefore, heretofore such aperture information transmitting means are formed independently of one another. Furthermore, since there are a number of full-aperture values and minimum-aperture values available, most of the aperture information transmitting means are so designed as to transmit information on the full-aperture value only which is essential for compensation of light metering; that is, they are not so designed as to transmit information on the minimum-aperture value.